Development of porosity in carbons from yeast grains by activation with alkali metal carbonates.

Cellular structured activated carbon samples were prepared with the aid of alkali carbonates X2CO3 (X = Li, Na, K, Rb, or Cs) from dry bread yeast with a milling procedure. The resultant carbon possesses a very large adsorption amount even for supercritical methane. The activation with Cs2CO3 gave the greatest surface area of 2420 m2 g(-1) from the subtracting pore effect method. The activation efficiency of X2CO3 (X = Li, Na, K, Rb, and Cs) was associated with the order of Gibbs free energy of X2O (X = Li, Na, K, Rb, and Cs) which should play an important role in the gasification. The carbon activated with Rb2CO3 gave the greatest adsorption amount of supercritical methane of 90 mg g(-1) at 0.9 MPa at 303 K.

Spectral tuning of photoactive yellow protein.

We report a theoretical study on the optical properties of a small, water-soluble photosensory receptor, photoactive yellow protein (PYP). A hierarchical ab initio molecular orbital calculation accurately evaluated the optical absorption maximum of the wild-type, as well as the lambda(max) values of 12 mutants. Electronic excitation of the chromophore directly affects the electronic state of nearby atoms in the protein environment. This effect is explicitly considered in the present study. Furthermore, the spectral tuning mechanism of PYP was investigated at the atomic level. The static disorder of a protein molecule is intimately related to the complex nature of its energy landscape. By using molecular dynamics simulation and quantum mechanical structure optimization, we obtained multiple minimum energy conformations of PYP. The statistical distribution of electronic excitation energies of these minima was compared with the hole-burning experiment (Masciangioli, T. [2000] Photochem. Photobiol. 72, 639), a direct observation of the distribution of excitation energies.

Possible Involvement of the Rat Hypothalamo-Neurohypophysial/-Spinal Oxytocinergic Pathways in Acute Nociceptive Responses.

Oxytocin (OXT)-containing neurosecretory cells in the parvocellular divisions of the paraventricular nucleus (PVN), which project to the medulla and spinal cord, are involved in various physiological functions, such as sensory modulation and autonomic processes. In the present study, we examined OXT expression in the hypothalamo-spinal pathway, as well as the hypothalamo-neurohypophysial system, which includes the magnocellular neurosecretory cells in the PVN and the supraoptic nucleus (SON), after s.c. injection of saline or formalin into the hindpaws of transgenic rats that express the OXT and monomeric red fluorescent protein 1 (mRFP1) fusion gene. (i) The numbers of OXT-mRFP1 neurones that expressed Fos-like immunoreactivity (-IR) and OXT-mRFP1 intensity were increased significantly in the magnocellular/parvocellular PVN and SON after s.c. injection of formalin. (ii) OXT-mRFP1 neurones in the anterior parvocellular PVN, which may project to the dorsal horn of the spinal cord, were activated by s.c. injection of formalin, as indicated by a significant increases of Fos-IR and mRFP1 intensity intensity. (iii) Formalin injection caused a significant transient increase in plasma OXT. (iv) OXT, mRFP1 and corticotrophin-releasing hormone mRNAs in the PVN were significantly increased after s.c. injection of formalin. (v) An intrathecal injection of OXT-saporin induced hypersensitivity in conscious rats. Taken together, these results suggest that the hypothalamo-neurohypophysial/-spinal OXTergic pathways may be involved in acute nociceptive responses in rats.

Fluorescent Visualisation of Oxytocin in the Hypothalamo-neurohypophysial/-spinal Pathways After Chronic Inflammation in Oxytocin-Monomeric Red Fluorescent Protein 1 Transgenic Rats.

Oxytocin (OXT) is a well-known neurohypophysial hormone that is synthesised in the paraventricular (PVN) and supraoptic nuclei (SON) of the hypothalamus. The projection of magnocellular neurosecretory cells, which synthesise OXT and arginine vasopressin in the PVN and SON, to the posterior pituitary plays an essential role in mammalian labour and lactation through its peripheral action. However, previous studies have shown that parvocellular OXTergic cells in the PVN, which project to the medulla and spinal cord, are involved in various physiological functions (e.g. sensory modulation and autonomic). In the present study, we examined OXT expression in the PVN, SON and spinal cord after chronic inflammation from adjuvant arthritis (AA). We used transgenic rats that express OXT and the monomeric red fluorescent protein 1 (mRFP1) fusion gene to visualise both the magnocellular and parvocellular OXTergic pathways. OXT-mRFP1 fluorescence intensity was significantly increased in the PVN, SON, dorsal horn of the spinal cord and posterior pituitary in AA rats. The levels of OXT-mRFP1 mRNA were significantly increased in the PVN and SON of AA rats. These results suggested that OXT was up-regulated in both hypothalamic magnocellular neurosecretory cells and parvocellular cells by chronic inflammation, and also that OXT in the PVN-spinal pathway may be involved in sensory modulation. OXT-mRFP1 transgenic rats are a very useful model for visualising the OXTergic pathways from vesicles in a single cell to terminals in in vitro preparations.

Prospective evaluation of a new anti-ulcer agent, ecabet sodium, for the treatment of Helicobacter pylori infection.

BACKGROUND: A new anti-ulcer agent, ecabet sodium, is active against Helicobacter pylori. AIM: To assess the efficacy of ecabet sodium for the eradication of H. pylori in patients with gastroduodenal diseases. METHODS: In a prospective, randomized and controlled study, patients infected with H. pylori were assigned to one of the following two groups: group LA, who received lansoprazole 30 mg o.d. + amoxycillin 500 mg q.d.s. after meals for 2 weeks, and group LAE, who received lansoprazole 30 mg o.d. + amoxycillin 500 mg q.d.s. + ecabet sodium 1000 mg b.d. after meals for 2 weeks. H. pylori status was determined before and at least 4 weeks after the therapy by rapid urease test, histology and a urea breath test. RESULTS: Of 101 patients (mean age 53 years, range 17-77 years, M/F: 68/33) enrolled in the study, 97 patients completed the protocol. Four patients were withdrawn because of diarrhoea (three from group LA) and skin rash (one from group LAE). The eradication of H. pylori was achieved in 28/48 (58%) patients in group LA and 38/49 (78%) patients in group LAE. The rate of eradication of H. pylori produced by the LAE treatment was significantly higher than that produced by the LA treatment. Side-effects appeared in two patients (malaise 1, skin rash 1) in group LAE and in seven patients (diarrhoea 6, dizziness 1) in group LA. These side effects disappeared spontaneously with cessation of the treatment. CONCLUSIONS: Ecabet sodium in combination with lansoprazole and amoxycillin increased the rate of eradication of H. pylori. Ecabet sodium appeared to reduce the incidence of diarrhoea as a side-effect of the dual LA therapy.

Pharmacokinetics and disposition of 4'-O-tetrahydropyranyladriamycin in mice by HPLC analysis.

The plasma level of 4'-O-tetrahydropyranyladriamycin (THP) declined rapidly after IV injection to mice, with a t1/2(alpha) of 0.453 min. Only 1.2 micrograms/ml THP was detected 2 min after injection of 5 mg/kg. The drug was immediately transferred to various tissues, where the drug levels were much higher than the plasma concentration. In the lung and spleen, 8.26 and 13.6 micrograms/g THP was present, respectively, 2 h after administration. Major metabolites of THP were 13-dihydro-THP, ADM, 7-deoxyadriamycinone, and 7-deoxy-13-dihydro-adriamycinone. Only 1.12% of the dose had been recovered in the urine by 48 h after injection as THP and its metabolites, according to analysis by HPLC fluorospectroscopy. The observed disposition of THP was compared with that of adriamycin (ADM). The plasma disappearance and tissue transfer of THP were faster than those of ADM. THP levels in the spleen and lung were higher and those in the heart and liver were lower than the corresponding ADM levels. Drug levels declined more quickly in most tissues in the case of THP than of ADM. Tissue distributions after single bolus and multiple injections were also compared and discussed.

PS-5 inhibition of a beta-lactamase from Proteus vulgaris.

Inhibition of Proteus vulgaris beta-lactamase by a new beta-lactam antibiotic, PS-5 was studied kinetically. There were two stages of inhibition. In the early stage, PS-5 inhibited the beta-lactamase by formation of a Michaelis-complex, and showed a competitive inhibition pattern with Ki-value of 0.22 microM (substrate, cephaloridine). After the formation of a Michaelis-complex between PS-5 and the enzyme, PS-5 showed a characteristic progressive inhibition pattern with time. Maximum inactivation was obtained after several minutes of preincubation of the enzyme with PS-5; as hydrolysis of PS-5 progressed, the enzyme activity was gradually recovered. Reactivation by an excess of substrate (cephaloridine) was not substantially realized in the presence of PS-5. PS-5 was very slowly hydrolyzed by the enzyme, showing a triphasic pattern in its reaction curve.

Deacetylation of PS-5, a new beta-lactam compound. II. Separation and purification of L- and D-amino acid acylases from Pseudomonas sp. 1158.

L-Amino acid acylase and D-amino acid acylase of Pseudomonas sp. 1158 which converted PS-5 to NS-5 (deacetylated PS-5) were separated and purified by sonication, streptomycin and ammonium sulfate fractionations, DEAE-Sephacel column chromatography and gel filtration. Molecular weight and the isoelectric point were estimated to be 75,000 and pI 5.45 for L-amino acid acylase and 100,000 and pI 4.95 for D-amino acid acylase.

Deacetylation of PS-5, a new beta-lactam compound. III. Enzymological characterization of L-amino acid acylase and D-amino acid acylase from Pseudomonas sp. 1158.

L-Amino acid acylase and D-amino acid acylase were stable below 50 degrees C, although the D-enzyme was more thermostable than the L-enzyme at higher temperatures. At 30 degrees C they showed the highest reaction velocity in phosphate buffer of pH 7.4. Hg++ and Cu++ severely inactivated their activity. Activation by Co++ was observed on L-amino acid acylase, but not on D-amino acid acylase. p-Chloromercuribenzoate inhibited both enzymes, whereas ethylenediamine tetraacetate was very inhibitory on L-amino acid acylase only. With N-acetyl- and N-chloroacetyl-amino acids as substrates, they were relatively stereo-specific. They acted as a peptidase on dipeptides and tripeptides. Although N-acetylglycine was attacked by the two enzymes, N-acetylglucosamine and N-acetylethanolamine were insusceptible. PS-5 was converted to NS-5 (deacetyl PS-5) by L-amino acid acylase as well as by D-amino acid acylase.

Synergism of PS-5 with penicillins and cephalosporins in antimicrobial activity against beta-lactam-resistant gram-negative microorganisms.

The in vitro synergism of PS-5 combined with various penicillins and cephalosporins in antimicrobial activity was examined in detail against beta-lactam-resistant Gram-negative bacteria. PS-5 showed a highly significant synergism in antimicrobial action against Escherichia coli RGN238 in combination with penicillins; and against Proteus vulgaris GN76 and Serratia marcescens T55 in combination with cephalosporins. It was moderately synergistic against Citrobacter freundii GN346, Enterobacter cloacae 45, Proteus morganii 111 and Enterobacter aerogenes E19, whereas no synergism was observed against Pseudomonas aeruginosa E2 and Klebsiella pneumoniae 130.

Studies on the biosynthesis of carbapenem antibiotics. II. Isolation and functions of a specific acylase involved in the depantothenylation of the OA-6129 compounds.

A specific acylase designated A933 acylase was isolated and purified to 90% protein homogeneity from Streptomyces fulvoviridis A933 17M9 which produces PS-5, epithienamycins A and C and MM 17880 together with minor carbapenem analogs, penicillin N and cephamycin C. This enzyme was found to catalyze the depantothenylation of OA-6129 carbapenems; the acyl exchange of OA-6129 carbapenems with acyl CoA's; the deacetylation of N-acetyl-L-amino acids; and the acylation of NS-5 and 6-aminopenicillanate with acyl CoA's, whereas the deacetylation of PS-5 and N-acetyl-D-amino acids; and the deacylation of benzylpenicillin and cephalosporin C were not observed. Similar enzyme activities were also detected in Streptomyces cattleya, Streptomyces cremeus subsp. auratilis and Streptomyces argenteolus which are all carbapenem producers.

Microbial phosphorylation of the OA-6129 group of carbapenem compounds.

The OA-6129 group of carbapenem antibiotics were phosphorylated with ATP by Brevibacterium ammoniagenes at the primary hydroxyl group of the C-3 pantetheinyl side chain. The phosphorylation resulted in the reduced antimicrobial activity against some Gram-positive bacteria, and the improved activity against some Gram-negative microbes. The increased resistance of the OA-6129 carbapenems due to phosphorylation was significant to mouse renal dehydropeptidase and moderate to the human enzyme. OA-6129A and B2 phosphates were found to be unsusceptible to A933 acylase, while OA-6129A and B2 were depantothenylated.

Studies on the biosynthesis of carbapenem antibiotics. IV. Beta-alanine in the C-3 pantetheinyl side chain of the OA-6129 group of carbapenems.

Radioactive beta-alanine was specifically incorporated into the beta-alanine moiety of the C-3 pantetheinyl side chain of the OA-6129 group of carbapenems by Streptomyces sp. OA-6129, while no added radioactive pantothenate was taken up into the mycelia. The extracellular concentrations of beta-alanine and pantothenate in the broth of Streptomyces sp. OA-6129 increased with the production of the carbapenems. The production levels of beta-alanine and pantothenate markedly differed between carbapenem-producing streptomycetes and nonproducers, with the exception of Streptomyces cattleya, a thienamycin producer, suggesting a possible relation of carbapenem biosynthesis with the levels of beta-alanine and pantothenate.

Studies on the biosynthesis of carbapenem antibiotics. III. Enzymological characterization of the L-amino acid acylase activity of A933 acylase.

A933 acylase, which is involved in exchange of the pantothenyl substituent of OA-6129 carbapenems with acetyl CoA, was characterized as an L-amino acid acylase with a molecular weight of 100,000 (+/- 8,000) and a pI value of 5.1. The highest L-amino acid acylase activity of A933 acylase was observed at 37 degrees C and pH 7 approximately 7.5 for N-chloroacetyl-L-phenylalanine. Unlike other amino acid acylases, A933 acylase was severely inhibited by cobalt ions and p-chloromercuribenzoate. The acylase also showed peptidase activity with some di- and tripeptides. A protein fraction with A933 L-amino acid acylase activity from blocked mutant 1501 lacked OA-6129A-depantothenylating activity.

Anthracycline metabolites from Streptomyces violaceus A262. I. Isolation of antibiotic-blocked mutants from Streptomyces violaceus A262.

Five mutant (or variant) strains producing new anthracycline antibiotics were derived from Streptomyces violaceus A262 by mutagenesis treatment. Strain SE1-625 showed a limited production of three known beta-rhodomycinone diglycosides while the parent strain produced numerous unidentified beta-rhodomycinone glycosides. Strain SU2-730 was an antibiotic-blocked mutant which produced only epsilon-rhodomycinone glycosides (named epelmycins). Strains SC-7 and SE2-2385 were variants which produced alpha-citromycinone glycosides (named yellamycins) and beta-isorhodomycinone glycosides (named obelmycins), respectively. Strain SE2-2385-A1 produced alpha 2-rhodomycinone glycosides (named alldimycins). Glycosidation-less mutants which accumulated only aglycone were also obtained. Isolation of these mutants or variants and preliminary identification of their anthracycline products are described.

Deacetylation of PS-5, a new beta-lactam compound, I. Microbial deacetylation of PS-5.

PS-5 was deacetylated to NS-5 (deacetylated PS-5) by l-amino acid acylase from porcine kidney and D-amino acid acylase from Streptomyces olivaceus but not by l-amino acid acylase from Aspergillus sp. Using PS-5, N-chloroacetyl-l-phenylalanine and N-chloroacetyl-D-valine as substrates, acylase producers were screened among facultative methanol-assimilating bacteria. Most of the microbes tested were active and could be classified into two groups of l-acylase producers and L-& D-acylase producers. Pseudomonas sp. 1158 which deacetylated the three substrates was chosen for further study. Cells of the bacterium entrapped in polyacrylamide gel and its acylase activities immobilized on DEAE-Sephadex were found to be useful for conversion of PS-5 to NS-5.

Deepoxidation of 16-membered epoxyenone macrolide antibiotics. I. Microbial deepoxidation and subsequent isomerization of deltamycins A1, A2, A3, A4 (carbomycin A) and X.

Carbomycin A (deltamycin A4) was deepoxidized to carbomycin A P1 by Streptomyces halstedii subsp. deltae (a deltamycins producer), favorably under anaerobic conditions. Carbomycin A P1 was spontaneously converted to geometric isomers designated carbomycins A P2 and A P3. This type of deepoxidation and subsequent isomerization was not limited to carbomycin A, but generally occurrable in other 16-membered epoxyenone macrolide compounds. Many bacteria and actinomycetes were also found to have an ability to deepoxidize deltamycins reductively. The chemical structures of carbomycins A P1, A P2 and A P3 were elucidated as shown in Fig. 3.

Pharmacological studies on carbapenem antibiotics. II. Isolation of a PS-5-inactivating factor from the rat kidney.

A factor responsible for the in vivo metabolism of PS-5 was isolated from the microsomal fraction of the rat kidney. This factor, which did not attack penicillins and cephalosporins, was enzymologically identified with particle-bound renal dipeptidase. Under the action of this factor, PS-5 was inactivated to give three products designated PS-5D I, PS-5D II and PS-5D III.

Mutagenesis of OA-6129 carbapenem-producing blocked mutants and the biosynthesis of carbapenems.

Streptomyces fulvoviridis A933 17M9 1501 is an A933 acylase-defective mutant derived from S. fulvoviridis A933 17M9 and thus produces the OA-6129 group of carbapenems and carbapenams. By further mutation of mutant 1501, 4 types of mutants (OA-6129 A + B1 + B2 producers; OA-6129 A + B2 producers; an OA-6129 A producer; non-producers) were obtained. The second type of mutant strains 4N 3607, 5NA 3949-40 and 5NE 252 proved useful for the fermentative production of carbapenem OA-6129 B2. These results of mutagenesis demonstrated that the sequence of carbapenem bioconversion in the horizontal route was hydroxylation at C-8----isomerization at C-6----sulfation at C-8 hydroxyl.

Controlled biosynthesis of neoviridogriseins, new homologues of viridogrisein. IV. In vitro synergism between neoviridogrisein II and the antibiotics of the mikamycin A group.

Neoviridogrisein II is a homologue of viridogrisein in which the hydroxyproline residue is replaced by proline. Neoviridogrisein II proved to be more active than the parent antibiotic against Gram-positive bacteria and Mycoplasma species. When neoviridogrisein II or viridogrisein was combined with griseoviridin, a non-peptidyl macrocyclic lactone, synergism was observed: maximum synergistic effect was observed for a combination ratio that depended on the test bacterium used. Neoviridogrisein II also exerted synergism when combined with mikamycin A and A-2315A.